Tubular container having polymeric liner ply

Abstract

A method of manufacturing multi-ply tubular containers for food products is provided including the steps of advancing a continuous body ply formed of paperboard towards a shaping mandrel and advancing a continuous polymeric liner ply adjacent to one surface of the paperboard body ply. The polymeric liner ply includes a moisture barrier layer and an adhesive layer defining one surface of the liner ply, wherein the adhesive layer includes a polymeric adhesive which is activated at a predetermined activation temperature. The body ply is heated to a temperature above the activation temperature of the adhesive, and the body ply and the liner ply are then passed in face-to-face contact through a nip to adhere the liner ply to the body ply. The body ply and liner ply are then wrapped around a shaping mandrel to create the tubular container. Accordingly, an advantageous tubular container can be manufactured having an unsupported and polymeric liner ply which is adhered to a body ply without the application of any separate adhesives.

That which is claimed: 
     
       1. A multi-ply tubular container for products comprising: at least one body ply formed of a fibrous paperboard, said body ply wrapped in a tubular shape having an inner surface; and   a polymeric liner ply having an inner surface facing the interior of the container and an outer surface adhered to said inner surface of said paperboard body ply, wherein said liner ply comprises; a polymeric moisture barrier layer; and   an adhesive layer defining the outer surface of said liner ply, wherein said adhesive layer comprises inner and outer sublayers each having a heat-activatible polymeric adhesive, said inner sublayer having an adhesive which is adhered to said barrier layer and said outer sublayer having a different adhesive which is adhered directly to the fibers of said body ply prior to said body ply being wrapped.     
     
     
       2. A tubular container as defined in claim 1 wherein said outer and inner sublayers of said adhesive layer are coextruded. 
     
     
       3. A tubular container as defined in claim 1 wherein the inner surface of said fibrous paperboard body ply is not coated prior to being adhered to said liner ply so that the fibers are generally exposed and the adhesive adheres thereto. 
     
     
       4. A tubular container as defined in claim 1 wherein said liner ply further comprises a polymeric seal layer defining the inner surface of said liner ply, and wherein said seal layer has a melting temperature higher than the temperatures at which said adhesives of said adhesive layer become activated. 
     
     
       5. A tubular container as defined in claim 4, wherein said seal layer includes a polyolefin polymer. 
     
     
       6. A tubular container as defined in claim 1, wherein the adhesive layer includes a polymer from the group consisting of ethylene vinyl acetate, ethylene acrylic acid, ethylene methacrylic acid, ethylene methyl acrylate and blends thereof. 
     
     
       7. A tubular container as defined in claim 1, wherein the outer sublayer of the adhesive layer includes ethylene methyl acrylate and the inner sublayer of the adhesive layer includes ethylene acrylic acid, and the barrier layer comprises polyester. 
     
     
       8. A tubular container as defined in claim 1, wherein said moisture barrier layer includes at least one of the group of polyester, nylon, ethylene vinyl alcohol copolymer and blends thereof. 
     
     
       9. A tubular container as defined in claim 1, wherein said barrier layer further comprises a metallized coating. 
     
     
       10. A tubular container as defined in claim 1, wherein the liner ply has a thickness of less than about three mils. 
     
     
       11. A tubular container as defined in claim 1, wherein said body ply and liner ply are helically wound. 
     
     
       12. A tubular container as defined in claim 1, wherein said body ply and said liner ply are rolled outwardly at an end of the tubular container to form a bead, and wherein said liner layer is elastically deformable and prevents said bead from unrolling.